A couple of different ways to accomplish this;
Option 1.
Add this custom CSS to center both the sections and they will appear stacked one above the other:
.site-info, .site-info-right {
float: none;
width: auto;
text-align: center;
margin-top: 10px;
}Option 2.
Add the same custom CSS as above to center the bottom footer area.
In ‘Settings’ > ‘Privacy’ deselect the privacy policy page so there is no page selected and click ‘Use this page’ to save. This will remove the auto generated link in the right of the footer.
Now go into the ‘Widgets’ area, and manually add a link to your privacy policy page in the ‘Footer Site Info’ widget area, in the same text widget that you are already using with your own copyright info.